Method of fastening outlet boxes



April 20, 1954 R. T. CATLIN METHOD OF FASTENING OUTLET BOXES 2 Sheets-Sheet 1 Filed June 14, 1952 INVENTOR. Robert T Coflin R. T. CATLIN METHOD OF FASTENING OUTLET BOXES April 20, 1954 2 Sheets-Sheet 2 Filed June 14, 1952 la ll !3 INVENTOR. Rober1 T. Cotli n Patented Apr. 20, 1954 D* STATES FAT ENT OFF ICE 'METHOD OF FASTENING'OUTLET BOXES Robert' T. Catfin, Stratford, Colin., assignor to Remington Armsfiompany, l ne., Bridgeport, Com., a corpo'aton of Delaware Application June H, 1952, Serial No. 293,(590

(CI. 29-148l 2 Cla'ms. l

This inventi'on relates to a method and means for fastening electrical outlet boxes and other members to elements of building structure. The invention is particularly directed toa method which utilizes the explosive Cartridge type' of tool.

Field experience with cartridge powered tools has revealed that such tools are extremely popular with the electrical trades in hanging outlet boxes. The most commonly used method requires the use of two nail-like studs which are driven through opposi-te corners of the rear wall of the box into the concrete or structural steel member to which the box is to be Secured. With this method it is difiicult to so direct the stud as to insure that it does not hit a knockout plate or one of the pre-punched holes in the back of the box. In addition, when fastening to conerete, particularly near an edge, the two studs are spaced so closely as to occasionally result in a crack in the concrete.

My fastening method for ou-tlet boxes is based upon the fact that all outlet boxes which I have examined, regardless of size or' shape, have one common feature. That common feature is at least one knockout hole of the standard seveneighths inch diameter for receiving one-half inch electrical conduit. I propose to secure to the building structure an explosively driven stud which passes centrally through a disk which, as to diameter and thickness, will fit closely enough in the selected knockout of the outlet box to aid in laterally positioning the box. I then fasten to the head of the stud a cupped Washer of large enough area to bear on the inner surface of the outlet box surrounding the selected knockout and thereby secure the box in contact With the element of building structure.

The exact nature of the invention as well as other objects and advantages thereof will be apparent from consideration of the following specification referring to the attached drawings in which:

Fig. 1 is a vertical sectional view through an outlet box Secured by my method to a structural steel member.

Referring to 'the drawngs by characters of reference, it will be seen that in Fig. 2 I have shown a conventional thread'ed stud I driven through the center of a blank steel disk 2 into a structural steel member 3 to which it is desired to secure anoutlet box. The disk 2 is of a diameter just under that of the selected outlet box knockout and is the type of disk commonly used with Cartridge powered tools to serve as a Washer liniting penetration of the stud into wooden members or to serve in reducing the spal'l and covering the cavity produced by spalling of concrete. such disks are not ordinarily perforated initially but are Secured as blanks in the muzzle of' the Cartridge powered tool, and the stud is fired therethrough.

After such a stud l has been set in a steel base 3 as in Fig. 2 or a stud la setin a concrete base 4 as in Fig. 3, the outlet box is secured thereto as described below.

The box 5, from which the selected knockout plate has been removed, is placed over the stud With the knockout hole 6 receiving the disk 2. A cupped retaining Washer 'I of larger diameter than the knockout hole, initially shaped as in Fig. 4, is then placed thereover, with the edges 8 of the cup engaging the inner surface of the box and the nut 9 run down on the threaded shank of the stud I. The nut should be tightened sufllciently to insure all-around contact of the edge of the Washer with the box surface and to resiliently deform the Washer to some extent but does not need to deform the central part of the Washer into contact with the disk. Although the center knockout is common to most boxes and will generally be used, it should be obvious that any other location may be used where such use seems advantageous to obtain clearance for fittings, wire, etc.

In this manner, the outlet box may be conveniently fastened in place and readily removed if later changes are required. Only a single stud is required per box and, since the studs are driven prior to placement of the box, the studs, and consequently the box, may be accurately located in accordance with building plans. Further, since the studs are driven prior to the installation of the box, standard safety guards may be employed on the driving tool rather than the cumbersome and often ineffective special guards or adapters used to drive within a box. Since a single stud in either concrete or steel has normally a pullout value in excess of 2,000` pounds, a single stud provides adequate strength while avoiding the cracking haz- 3 ard associated with studs driven too closely adjacent one another.

The modifications shown in Figs. 5, 6, '7, and 8 show alternate stud designs in which the variations are in the method of securing the cupped Washer to the stud and each is briefiy described below.

Referring to Fig. 5, it may be seen that the stud 'a and disk 2 are of identical types and are Secured in the same way as in the previous forms above described. In this case, however, I have employed a combined retaining Washer and nut IO formed preferably of spring stock and cut substantiaily radially to provide a pair of tongues II and z which engage the thread of the stud in the manner of certain well-known self-looking spring nuts. One or more holes !3 provide for engagement by a spanner type wrench for application or removal, although it should be obvious that a spring nut of this type may be applied simply by driving it over the shank of the stud with a hollow center punch.

The form shown in Fig. 6 is closely analogous to that of 5 but is designed for application to a stud !4 which is provided with one or more looking grooves !5. In this case the spring washer |6 is formed with a pair of opposed looking tabs ll and upon being driven over the stud with a hollow center punch these tabs engage a groove l5.

In the form shown in Fig. '7, the stud I& is by difierential heat treatment or by a known composite Construction provided with a soft tip s over which my preferred type of retaining washer 'I may be applied and Secured by riveting over the soft tip.

In the form shown in Fig. 8, I have utilized the preferred type of stud 'a and disk 2 with a combined retaining Washer and nut, which may comprise a Washer portion 20 and nut portion 2! either formed integrally or made substantially so either by mechanically interlocking the two portions or by joining them by brazing or other fusion process.

Although I have illustrated and described several specific forms of my invention, I wish it to be understood that I do not consider my invention to be limited by these forms specifically illustrated. For the exact limits upon my invention, reference may be had to the claims appended hereto.

Iclaim:

1. In the art of securing to a base a member adapted to contact said base and having an aperture therein, the method which comprises supporting in contact with said base a plate capable of being received in said aperture, forclbly propelling through said plate and into said base a stud provided with a head extending outwardly from said plate, mounting said member on the base with the aperture in said member receiving said plate, and securing to said head means engaging the surface of said member surrounding said aperture.

2. In the art of securing to a base a member adapted to contact said base and having a circular aperture therein; the method which comprises supporting in contact with said base a disk of slightly less diameter than the diameter of said aperture, forcibly propelling through said disk and into Secured relation in said base a stud provided with a threaded head, mounting said member on said base with the circular aperture in said member receiving said disk, applying to said threaded head a cupped Washer of larger diameter than said aperture with the edge portion in engagement with said member, and applying a nut to said threaded head to retain said Washer thereon.

References Cited in the file oi' this patent UNITED STA'I'ES PATENTS Number Name Date 1,592,020 Weston July 13, 1926 2,455,825 Temple Dec. 7, 1948 2,479,431 Temple Aug. 16, 1949 2,498,221 Poupitch Feb. 21, 1950 2,575,079 Temple Nov. 13, 1951 FOREIGN PATENTS Number Country Date 286,190 Italy June 3, 1931 

